Automation of 99 Tc extraction by LOV prior ICP-MS detection: Application to environmental samples Rogelio Rodríguez a , Luz Leal a,n , Silvia Miranda a , Laura Ferrer b , Jessica Avivar b , Ariel García c , Víctor Cerdà d a Renewable Energy and Environmental Protection Department, Advanced Materials Research Center (CIMAV) S.C., Chihuahua 31109, Chihuahua, Mexico b Environmental Radioactivity Laboratory-LaboRA, University of the Balearic Islands, Palma E-07122, Spain c Nuclear Medicine Area, International Center of Medicine (CIMA), Chihuahua 31217, Chihuahua, Mexico d Laboratory of Environmental Analytical Chemistry, University of the Balearic Islands, Palma E-07122, Spain article info Article history: Received 12 December 2013 Received in revised form 28 March 2014 Accepted 21 April 2014 Available online 7 July 2014 Keywords: 99 Tc LOV Environmental samples Solid phase extraction ICP-MS abstract A new, fast, automated and inexpensive sample pre-treatment method for 99 Tc determination by inductively coupled plasma-mass spectrometry (ICP-MS) detection is presented. The miniaturized approach is based on a lab-on-valve (LOV) system, allowing automatic separation and preconcentration of 99 Tc. Selectivity is provided by the solid phase extraction system used (TEVA resin) which retains selectively pertechnetate ion in diluted nitric acid solution. The proposed system has some advantages such as minimization of sample handling, reduction of reagents volume, improvement of intermediate precision and sample throughput, offering a significant decrease of both time and cost per analysis in comparison to other flow techniques and batch methods. The proposed LOV system has been successfully applied to different samples of environmental interest (water and soil) with satisfactory recoveries, between 94% and 98%. The detection limit (LOD) of the developed method is 0.005 ng. The high durability of the resin and its low amount (32 mg), its good intermediate precision (RSD 3.8%) and repeatability (RSD 2%) and its high extraction frequency (up to 5h 1 ) makes this method an inexpensive, high precision and fast tool for monitoring 99 Tc in environmental samples. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Technetium was the first radioactive element produced artificially. 99 Tc is one of the Tc isotopes with a long half-life (T 1/2 ¼ 2.1  10 5 y). Large amounts of 99 Tc have been produced and released to the environment from human nuclear activities such as nuclear weapons testing, nuclear fuel cycle, nuclear accidents and nuclear medicine activities including a wide variety of diagnostic tests (e.g., renal, thyroid, cardiac gammagraphy, and detection of internal infectious process), making 99 Tc the only environmentally significant Tc isotope [1,2]. The predominant chemical form of 99 Tc is the pertechnetate ion (TcO  4 ) in oxidizing environments, being very stable. The pertechnetate ion is hardly complexed with organic compounds in aerobic environments. Moreover the high water solubility and environmental mobility of Tc (in the form of TcO  4 ) as well as its long half-life, makes 99 Tc a radionuclide of high environmental interest. Thus, becoming its accurate determination in various types of samples mandatory [1,3]. Due to the extremely low concentration of 99 Tc in environ- mental matrices, the sample preparation, preconcentration, chemical separation and purification for removal of potential interferences for 99 Tc detection are the most important issues governing the accurate determination of this analyte. The long half-life and therefore low specific activity of 99 Tc (0.64 Bq ng 1 ), makes mass spectrometry (MS) techniques poten- tially sensitive tools for measurement of 99 Tc [4–7]. ICP-MS is the most widely and frequently used mass spectrometric technique for measurement of 99 Tc in many types of environmental samples, due to its high sensitivity and rapidity [8,9]. However, one of the main limitations of this technique is that high concentration of dissolved solids should be avoided in order to enlarge the good performance of the instrument, making necessary matrix and interferences removal prior introduction into the ICP-MS. There- fore, a sample clean-up prior to analysis is mandatory. Another challenge in 99 Tc measurement by ICP-MS is to overcome isobaric and molecular interferences. Chemical separation techniques used for radiometric methods can also be applied in the mass spectro- metric determination of 99 Tc. The main difference is that the separation methods used for mass spectrometric measurement are focused on the removal of stable isotopic interferences with Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/talanta Talanta http://dx.doi.org/10.1016/j.talanta.2014.04.093 0039-9140/& 2014 Elsevier B.V. All rights reserved. n Corresponding author. E-mail address: luz.leal@cimav.edu.mx (L. Leal). Talanta 133 (2015) 88–93